What is the wavelength of a ruby laser?

The wavelength of a ruby laser is 694nm, which is characteristic of the specific type of laser that utilizes a synthetic ruby crystal as its gain medium. Ruby lasers emit light in the red part of the visible spectrum and are known for their deep red color. The 694nm wavelength is particularly important in applications such as tattoo removal, hair removal, and other dermatological procedures, as it effectively targets melanin in the skin and hair follicles.

In contrast, the other choices represent wavelengths associated with different types of lasers or light sources. For example, 755nm is commonly associated with Alexandrite lasers, 587nm with certain gas lasers, and 800nm is often linked to diode lasers. Each of these wavelengths has its own specific utility in laser treatments, but only the 694nm wavelength is indicative of the ruby laser.